Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: djay230 on January 18, 2012, 08:20:29 PM
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We have the name of the substance (Calcium Chloride)
and we are supposed to find the name of the other possible substance which is currently unknown is either :
Sodium Acetate
Sodium Nitrate
Sodium Sulphate
We had to use a concentration of Calcium Chloride and mix it with the "unknown" solution (100ml of cacl, 50ml of the unknown) we drained it into filter paper and now we have the mass of the substances after being drained...i have no idea what to do, any ideas?
The precipitate that was drained with the filter paper is a white solid
i have no idea what to do!
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OK, you have 4 different chemical names. Chemistry doesn't work on names. ;) So lets start by translating these names of chemicals you mixed into balanced chemical equations.
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OK, you have 4 different chemical names. Chemistry doesn't work on names. ;) So lets start by translating these names of chemicals you mixed into balanced chemical equations.
Sodium Acetate
Sodium Nitrate
Sodium Sulphate
and Calcium Chloride so...
I am pretty new to chemistry, gonna need some help...i have no idea what to do
how would i find out which one is the unknown substance from
Sodium Acetate
Sodium Nitrate
Sodium Sulphate
?????????
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Have you learnt about solubility rules?
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Have you learn about solubility rules?
not sure, please tell me why, i might have been sick that day, :(
i am really confused, i understood titration fine and the other units, but im really stuck on this one, trying to figure it out for hours can someone justplease help me?
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As Arkcon said above, try to write down the chemical equations. The reactions that take would be double replacement reactions in concept.
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As Arkcon said above, try to write down the chemical equations. The reactions that take would be double replacement reactions in concept.
i did that, it doesn't help at all...how do i find which one is the known substance that she gave me?
i am looking at 3 equations, BUT how do i find out which is the substance she gave me....
does anyone know the answer to this? Any teachers, university students? anyone thats above the grade 11?
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OK, you have 4 different chemical names. Chemistry doesn't work on names. ;) So lets start by translating these names of chemicals you mixed into balanced chemical equations.
i dont think you understand the question, the teacher gave us an UNKNOWN substance, then calcium chloride, we mixed it...
she said the possible substances the unknown can be is
Sodium sulfate
sodium acetate
or
sodium nitrate
i dont know how to find out the unknown.
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Can you show me what you did? If you indeed did them correctly, and consider the solubility rule as UG mentioned, you'll be able to identify the unknown solution.
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Can you show me what you did? If you indeed did them correctly, and consider the solubility rule as UG mentioned, you'll be able to identify the unknown solution.
what do you mean solubility rule?
what i did was first take the cacl and dilute it with water
then use the given solution (it was a liquid)
mix the given solution with the dilluted cacl and then drain the precipitate in the paper filter
THE DRAINED PRECIPITATE WAS A WHITE SOLID!
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When you mixed the two solutions together, the ions swapped partners. The other posters are saying you should write chemical equations to find out what those product compounds are. One of those products precipitated out. If you look up "solubility rules" in your textbook or online, those will help you pick which compound is the precipitate.
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I want to see you write out balanced chemical reactions, using the symbolic letters used in the periodic table of elements, to describe the reactants, and the products. Then, once you've determined the possible products, we will again use the periodic table of elements to try to figure out how we can differentiate the 3 possible products, by their mass.
This is how we help, on this forum. We don't give complete answers, we give hints to help you learn for yourself. Sorry are hints so far have been too subtle, but there's no need to retype the question again and again, we can scroll up and read it. You're just lengthening your thread, pointlessly.
Here's another tip ... THE COLOR WHITE HAS NO MASS ASSOCIATED WITH IT. Elements and compounds do however.
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I want to see you write out balanced chemical reactions, using the symbolic letters used in the periodic table of elements, to describe the reactants, and the products. Then, once you've determined the possible products, we will again use the periodic table of elements to try to figure out how we can differentiate the 3 possible products, by their mass.
This is how we help, on this forum. We don't give complete answers, we give hints to help you learn for yourself. Sorry are hints so far have been too subtle, but there's no need to retype the question again and again, we can scroll up and read it. You're just lengthening your thread, pointlessly.
Here's another tip ... THE COLOR WHITE HAS NO MASS ASSOCIATED WITH IT. Elements and compounds do however.
you dont understand, i dont know this chem stuff, it is pointless me writing it out on the forum when i did infront of me and its no help, the forum i understand you dont want to give answer so i dont learn, but i have no choice.
I do NOT understand ANY of it, its all infront of me, i've been looking stuff up the whole day what else do you want me to do?
can someone just explain to me the solubility rules and what is a precipitate? how does this all relate, etc.
i will learn in time, i will log off in 1 hour, if help is not provided i guess i fail the exam...no sympathy on this forum these days...begging for help and not even one chooses to explain anything to me.
w/e if this is how chem is going to be i think im just going to drop out, even my teacher would explain this to me but ive been dead sick for the past week and i cant get help on the internet...
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*SIGH* There are two ways to solve this problem, one is easier than the other. Please look up the term "solubility rules" in the index of your textbook. Or do an online search. See if something jumps out at you when you compare that info to the starting info you have in the assigned problem.
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The calcium compound that is 'insoluble' is the precipitate.
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The calcium compound that is 'insoluble' is the precipitate.
going to bed in 10 minutes, i have no idea what solubility is...or a insoluble
can someone please explain how the chart works? no idea looking at it how anything works...
i do see the sulfate, dont see acetone
really confused, am i looking for sodium acetate, sodium nitrate, sodium sulphate to be insoluble or
sodium chloride, calcium sulfate? i really have no idea, so many possible combinations what am i looking for...
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The calcium compound that is 'insoluble' is the precipitate.
going to bed in 10 minutes, i have no idea what solubility is...or a insoluble
can someone please explain how the chart works? no idea looking at it how anything works...
i do see the sulfate, dont see acetone
really confused, am i looking for sodium acetate, sodium nitrate, sodium sulphate to be insoluble or
sodium chloride, calcium sulfate? i really have no idea, so many possible combinations what am i looking for...
nvm, i found a table that makes sense...
ok so i understand that acetone and nitrate are apparently "soluable"
i think that means it will dissolve, therefore those 2 cannot be the unknown solution since it would not give me a precipitate but a solution.
Therefore the sodium sulphate must be the unknown because when mixed with calcium it is low soluable .
dont know if that means its still a liquid or not but low soluble sounds better than soluble.
also, with the mass of the precipitate, what can i do with that?
i used 100ml of the cacl, and 50ml of the sodium sulphate, the total mass of the precipitate would be what?
also, can anyone help me with a balanced equation for this?
cacl2 + NaSO4 ----> CaSO4 + NaCl2 ???
i am really bad at chem,
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The calcium compound that is 'insoluble' is the precipitate.
going to bed in 10 minutes, i have no idea what solubility is...or a insoluble
can someone please explain how the chart works? no idea looking at it how anything works...
i do see the sulfate, dont see acetone
really confused, am i looking for sodium acetate, sodium nitrate, sodium sulphate to be insoluble or
sodium chloride, calcium sulfate? i really have no idea, so many possible combinations what am i looking for...
nvm, i found a table that makes sense...
ok so i understand that acetone and nitrate are apparently "soluable"
i think that means it will dissolve, therefore those 2 cannot be the unknown solution since it would not give me a precipitate but a solution.
Therefore the sodium sulphate must be the unknown because when mixed with calcium it is low soluable .
dont know if that means its still a liquid or not but low soluble sounds better than soluble.
also, with the mass of the precipitate, what can i do with that?
i used 100ml of the cacl, and 50ml of the sodium sulphate, the total mass of the precipitate would be what?
also, can anyone help me with a balanced equation for this?
cacl2 + NaSO4 ----> CaSO4 + NaCl2 ???
i am really bad at chem,
mhh gonna check this in the morning
but i beielve it is
cacl2 + na2so4 -----> caso4 + 2nacl
hope its right, and for anyone else out there that can tell me what the mass of the precipitate can be used for i'd gladly appreciate it...
feeling better from my sickness dont know if i'll go to school tomorrow, have a fever but atleast i learned what i need to for my exam
so if anyone can tell me if a question can be used with the mass of the precipitate or if the whole purpose of this was to understand that precipitate was formed which meant it had to be a unknown solution of sodium sulphate....
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You got it generally right - if there was a precipitate (solid appearing in the resulting solution after solutions were mixed), something was insoluble - and the only insoluble substance that can produced here (as you checked using solubility rules) is a calcium sulfate. As your solution of the calcium chloride already contained calcium ions, it was apparently mixed with a solution containing sulfate ions, and calcium sulfate precipitated out of the solution.
You listed volumes of the solutions that were mixed - do you know concentrations? If so, you can try to use stoichiometry to calculate how much precipitate should be produced. That's where the masses come into the question. If the real mass of the precipitate is close to the calculated mass of calcium sulfate, that's additional confirmation that you are right.
But I don't expect it to be similar (which still doesn't mean you are wrong). There are several other factors that should be taken into account here. I doubt you know these factors yet.
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As Arkcon said above, try to write down the chemical equations.
Sorry guys, but asking djay to start with reaction equations was completely off. UG was right pointing at solubility rules - not knowing nor understanding these it is pointless to start writing reactions, as you can't predict products.
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You got it generally right - if there was a precipitate (solid appearing in the resulting solution after solutions were mixed), something was insoluble - and the only insoluble substance that can produced here (as you checked using solubility rules) is a calcium sulfate. As your solution of the calcium chloride already contained calcium ions, it was apparently mixed with a solution containing sulfate ions, and calcium sulfate precipitated out of the solution.
You listed volumes of the solutions that were mixed - do you know concentrations? If so, you can try to use stoichiometry to calculate how much precipitate should be produced. That's where the masses come into the question. If the real mass of the precipitate is close to the calculated mass of calcium sulfate, that's additional confirmation that you are right.
But I don't expect it to be similar (which still doesn't mean you are wrong). There are several other factors that should be taken into account here. I doubt you know these factors yet.
Does anyone know how to find the limiting reagent of
Cacl2 + na2SO4 -----> caso4 + 2nacl
For caso4?
I cannot find it :(
Help please !
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Does anyone know how to find the limiting reagent of
Cacl2 + na2SO4 -----> caso4 + 2nacl
For caso4?
What you wrote suggests you have no idea what the limiting reagent is. You need to know amounts of both reacting substances to be able to say which one is a limiting reagent. For a given reaction equation it is not always the same substance.
See
http://www.chembuddy.com/?left=balancing-stoichiometry&right=stoichiometric-calculations
and
http://www.chembuddy.com/?left=balancing-stoichiometry&right=limiting-reagents
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Does anyone know how to find the limiting reagent of
Cacl2 + na2SO4 -----> caso4 + 2nacl
For caso4?
What you wrote suggests you have no idea what the limiting reagent is. You need to know amounts of both reacting substances to be able to say which one is a limiting reagent. For a given reaction equation it is not always the same substance.
See
http://www.chembuddy.com/?left=balancing-stoichiometry&right=stoichiometric-calculations
and
http://www.chembuddy.com/?left=balancing-stoichiometry&right=limiting-reagents
Cacl2 + naso4 ---->2nacl + caso4
How do you find it :(
I need to know how to find limiting reagent and not to read on balancing equations
I only have the mass of caso4 how would I use that ?
If I have the concentration how would I use that?
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It's time to use some logic...
1) Do you know the concentration of the CaCl2 that was in your starting solution?
2) Can you use this information to find the total moles of calcium that you added?
3) From your balanced chemical reaction, do you know what physical state each of the four components would be in your final mixture?
4) Do you know the concentration of the unknown salt? (My guess is that this answer is "no", but if it is "yes", skip the next question and solve as a limiting reagent question.)
5) From the amount of calcium that you added, can you estimate a range of masses for the solid that you might expect, based on different values for the concentration of the unknown salt?
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I need to know how to find limiting reagent and not to read on balancing equations
Sigh. Neither of the pages linked to talks about balancing equations. Apparently you have not even visited them.
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It's time to use some logic...
1) Do you know the concentration of the CaCl2 that was in your starting solution?
2) Can you use this information to find the total moles of calcium that you added?
3) From your balanced chemical reaction, do you know what physical state each of the four components would be in your final mixture?
4) Do you know the concentration of the unknown salt? (My guess is that this answer is "no", but if it is "yes", skip the next question and solve as a limiting reagent question.)
5) From the amount of calcium that you added, can you estimate a range of masses for the solid that you might expect, based on different values for the concentration of the unknown salt?
thanks for giving me a detailed answer but i took the exam today, it was okay i think i messed up on some of the questions that was based on vocabulary. Really appreciate you being one of the very few people that gave a valid response to my questions and frustrations.